276
The Term “Adherence” in Patients with Chronic Kidney
Disease: The Facts
When the patient reaches to end-stage renal disease, clinical comorbidities like
renal anemia, secondary hyperparathyroidism, and infection are much morely added
to hypertension that all are involved in the clinical course and survival of the CKD
patient. Therefore, progression of CKD is generally associated with introduction of
new drugs to be taken by the patient to minimize the effects of these disorders that
might be difficult to be controlled only by dietary measures and dialysis therapy
itself. Pre-dialysis patients have been shown to be treated with a mean of 6–12
medications [ 2 , 7 ]. Moreover, a recent study on maintenance dialysis therapy
revealed a median number of 19 pills with one-quarter of them taking >25 medica-
tions daily [ 2 , 8 ]. In the light of these findings, the term “drug adherence” defined
as patient’s respect to taking his/her prescribed medication(s) is a significant issue
in this patient population. Additionally, adherence in hypertension emphasizes the
need for agreement between the physician and patient in the treatment of hyperten-
sion and consequently focuses on the patient’s ability and willingness to accept an
antihypertensive regimen. Moreover, the World Health Organization (WHO) says
that, “adherence is a person’s behavior concerning taking medication, following a
diet, and making changes in lifestyle in accordance with a medical or non-medical
health professional recommendations” [ 9 ].
Studies in Chronic Kidney Disease Population
Adherence might be lower in these patients due to such a high pill burden in patients
with CKD. Supporting this idea, a low adherence to drug treatments (down to 3%)
as well as a low adherence to nutritional recommendations has been reported in
CKD and dialysis patients [ 2 , 10 ]. Moreover, adherence to drug therapy in CKD
was assessed via the medication possession ratio [ 5 ] and the Morisky questionnaire
[ 6 ]. The findings of these abovementioned studies revealed that more than 30% of
the study patients which is a quite significant number were poorly adherent to medi-
cal therapy. Interestingly, a study measuring drug adherence in CKD patients
reported improving drug adherence (by self-report) while renal function further
declines – indicating both doctors and patients have become more interested in
blood pressure control with the progression of CKD [ 11 ]. A pre-dialysis study
showed that medication nonadherence was lower (17.4%) at the baseline period of
the study than after 1 year of the study (26.8%) [ 11 ]. Compared to the baseline
period, the percentage of adherent patients who became nonadherent (22%) was
lower than the percentage of nonadherent patients who became adherent (50%)
[ 11 ]. Similar numbers were demostrated in CKD patients not on dialysis by Moreira
et al. (18.5%) [ 12 ] – using the self-report method and a drug profile – and by Lee
et al. (18%) [ 13 ], based on two methods, pill count and electronic monitoring. It is
A. Kirkpantur and B. Afsar